FERMENTATION POTENTIAL OF LACTOBACILLUS RHAMNOSUS AND LACTOBACILLUS ACIDOPHILUS IN DATE SYRUP TO DEVELOP A FUNCTIONAL FERMENTED BEVERAGE: A COMPARATIVE STUDY

摘要

In this work, capability of the unbleached date syrup was studied as an inexpensive substrate to prepare a nondairy probiotic beverage by Lactobacillus strains of acidophilus and rhamnosus. The growth kinetics, pH, acidity, sugars, organic acids, phenolic content and antioxidant activity were investigated over the 48-h fermentation at 37C, whereas cell viability was determined for 4 weeks at 4C. Consequently, both lactobacilli could grow in date syrup without nutrient requirements and could increase to more than 108 cfu/mL after 20 h. L. acidophilus with the highest pH decrease and sugar consumption showed much better growth rate than another bacterium. Produced gluconic acid (4.25 g/L) was significantly higher than lactic acid level (3.75 g/L). Moreover, an insignificant difference in values of total phenolics and antioxidant capability by fermenting with both lactobacilli was found. L. acidophilus was more capable to survive and its viable cells remained at 1.64 × 107 cfu/mL after 4 weeks.